Thuidiaceae

Diagnosis: Plants small and slender, in typically stiff, dull, mostly green to yellow-green, often lax mats. Stems creeping, to ca. 6 cm long, regularly 2-pinnate; paraphyllia moderately abundant on stems, sparse at base of primary branches, none on secondary branches and distal end of primary branches, filamentous, uniseriate, unbranched, 2-5 cells long, the distal cell truncate. Stem and branch leaves strongly differentiated, the stem leaves appressed when dry, erect-spreading when moist, broadly ovate-triangular, 0.3-0.6 mm long, ± abruptly broadly acuminate, concave, not plicate, short decurrent; margins crenulate-papillose throughout, narrowly recurved below; costa single, broad, ending in but not filling the acumen; cells short-rectangular, pluripapillose with 2-5 papillae/cell. Secondary branch leaves incurved when dry, spreading when moist, laxly disposed so that branches obviously exposed when dry, ovate, 0.15-0.25 mm long, obtuse to broadly acute, concave, not plicate, subauriculate; margins regularly crenulate-papillose, plane; costa single, ending ca. 2/3 the leaf length, not or scarcely projecting at back; cells ± quadrate, pluripapillose, ca. 6 µm wide. Seta elongate, roughened throughout, orange, 0.7-2 cm long; capsules horizontal to pendent, short-cylindric, 0.5-1 mm long; annulus of 1-2(-3) rows of small, rectangular, firm-walled cells; operculum obliquely long-rostrate; exostome teeth yellow to yellow-brown, shouldered, bordered, on the front surface cross-striolate below, becoming papillose and then coarsely papillose above. Spores 14-18 µm diameter.

Distribution: Southern Central America, Caribbean, lowland South America

Ecology: Growing on limestone and old wood, in mostly mesic to humid lowland forest, to ca. 300 m.

Basionym: Thuidium scabrosulum Mitt.

Basionym Citation: Journal of the Linnean Society, Botany 12: 574. 1869.

Other Published Figures: W. R. Buck. 1998. Pleurocarpous mosses of the West Indies. Plate 76 (1-11).